Power semiconductor modules incorporating switching elements and diodes connected antiparallel to the switching elements are widely used for power converters that perform conversions such as a DC-AC and DC-DC conversion. A Si (silicon) semiconductor has been conventionally used for switching elements and diodes; however applications of a wide-bandgap semiconductor, which is represented by a SiC (silicon carbide) semiconductor, have been developed in recent years. The SiC semiconductor features low power loss, operability at high temperatures, high-withstand voltage, etc. compared to the Si semiconductor; therefore using the SiC semiconductor enables reduction in size and power loss of a semiconductor module, and in addition it enables not only reduction in size of cooling unit to which the power semiconductor module is mounted, but also improvement in efficiency of a power inverter using the power semiconductor module.
Using the SiC semiconductor for both switching elements and diodes will further enhance the effect as described above. However, the construction of the switching elements is complex compared to that of the diodes, so there also remains manufacturing problems in using the SiC semiconductor for the switching elements. Therefore, there has been proposed a semiconductor module in which using the Si semiconductor for the switching elements and the SiC semiconductor only for the diodes, the Si switching elements and SiC diodes are arranged on the same metal base (refer to, for example, Patent Document 1).